Videos of Crystal Growth

The videos on this page show the growth of crystals from a supersaturated solution of tartaric acid with a small amount of an organic dye (crystal violet) added.

Crystal violet is a pH indicator and turns yellow at pH < 2. The solution is yellow due to the acidity of dissolved tartaric acid, while crystal violet in the crystal environment takes on higher-pH colors (red, green, blue), presumably because water, i.e., a proton donor,  is lacking.

The videos demonstrate the variety of crystal habits that tartaric acid can take. Many of the videos show nucleation, i.e., the formation of seed crystals in the solution. Apparently, this is mostly homogeneous nucleation, i.e., formation of a seed crystal from order-parameter fluctuations in the solution. One notable exception is DSC_4568, which, apparently, is showing both homogeneous, and heterogeneous nucleation.

Crystallization can happen rather rapidly, depending on the conditions (temperature, saturation, etc.). Several of the videos are live speed, while others are accelerated by a factor of 2, 4, or 8 (indicated below).

While this page is under construction, please look at the videos at listed here

320x240 pixels:

DSC_3086 (live speed)

DSC_3188 (live speed)

DSC_3189 (live speed)

DSC_3380 (live speed)

 

640x480 pixels. HD (1980x1080) available upon request

DSC_4008 (2x): nucleation near the center about 8s into the movie

DSC_4525 (live speed): this one was really fast. It went off in a burst within the time it took to stick the slide under the microscope

DSC_4526 (4x)

DSC_4568 (4x): homogeneous nucleation near the upper left-hand corner about 9 s into the movie, and heterogeneous nucleation after about 35 s near the lower right-hand corner where a speck of "dirt" is seen before the crystal begins to grow. Interestingly, the heterogeneously nucleated crystal is different from the others in habit (and apparently crystal structure), and in color (the way the crystal violet is embedded in the crystal)

DSC_4602 (4x)